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<title>Deprecated Features (Using the GNU Compiler Collection (GCC))</title>

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<h3 class="section" id="Deprecated-Features-1"><span>7.11 Deprecated Features<a class="copiable-link" href="#Deprecated-Features-1"> &para;</a></span></h3>

<p>In the past, the GNU C++ compiler was extended to experiment with new
features, at a time when the C++ language was still evolving.  Now that
the C++ standard is complete, some of those features are superseded by
superior alternatives.  Using the old features might cause a warning in
some cases that the feature will be dropped in the future.  In other
cases, the feature might be gone already.
</p>
<p>G++ allows a virtual function returning &lsquo;<samp class="samp">void *</samp>&rsquo; to be overridden
by one returning a different pointer type.  This extension to the
covariant return type rules is now deprecated and will be removed from a
future version.
</p>
<p>The use of default arguments in function pointers, function typedefs
and other places where they are not permitted by the standard is
deprecated and will be removed from a future version of G++.
</p>
<p>G++ allows floating-point literals to appear in integral constant expressions,
e.g. &lsquo;<samp class="samp"> enum E { e = int(2.2 * 3.7) } </samp>&rsquo;
This extension is deprecated and will be removed from a future version.
</p>
<p>G++ allows static data members of const floating-point type to be declared
with an initializer in a class definition. The standard only allows
initializers for static members of const integral types and const
enumeration types so this extension has been deprecated and will be removed
from a future version.
</p>
<p>G++ allows attributes to follow a parenthesized direct initializer,
e.g. &lsquo;<samp class="samp"> int f (0) __attribute__ ((something)); </samp>&rsquo; This extension
has been ignored since G++ 3.3 and is deprecated.
</p>
<p>G++ allows anonymous structs and unions to have members that are not
public non-static data members (i.e. fields).  These extensions are
deprecated.
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